Conventionally, a wireless ad-hoc network and a wired network are connected to each other at a gateway, and data is transmitted from plural sending terminals connected to the wireless ad-hoc network to respective receiving terminals connected to the wired network.
In the transmission, an effective band available for the data transmission between each of the sending and receiving terminals depends on routing from the sending terminal to the gateway and the network status, thus resulting in unfairness among the sending terminals.
In order to reduce such unfairness, various techniques are known for securing fairness in transmission band among plural sending terminals connected to the wireless ad-hoc network (for example, see Patent References 1 to 6).
Patent Reference 1 discloses a technique for detecting a bottleneck in the transmission band, which is generated at a relay node in the wireless ad-hoc network, so as to decrease a transmission rate at a source apparatus.
In addition, Patent Reference 2 discloses a technique for searching packet content at each relay node and scheduling an order of transmitting each packet.
In addition, Patent Reference 3 discloses a technique for prorating, at each relay node, a transmission band available for the relay node according to the number of terminals that are relayed (subordinate terminals) so as to achieve a fair data transmission amount among the subordinate terminals.
In addition, for a method of controlling the transmission amount for the sending terminals according to a communication band on a transmission path, Patent Reference 4 discloses a technique for estimating the transmission band for the communication network at a receiving side and indicating, to the sending terminals, the data transmission amount based on the estimated transmission band.
In addition, Patent Reference 5 discloses a technique for optimizing an update frequency of routing information by increasing the update frequency between unstable nodes or links, and decreasing, conversely, the update frequency between stable nodes or links. Patent Reference 5 further discloses a technique for estimating, at each relay node, stability (fault tolerance) of the nodes and links on the transmission path.
In addition, Patent Reference 6 discloses a technique for detecting a bottleneck link on the transmission path by obtaining, one by one, band information of each link between a sending terminal and a relay node, between relay nodes, and between a relay node and a receiving terminal, so as to perform transmission and reception according to the band of the detected link.                Patent Reference 1: Japanese Unexamined Patent Application Publication No. 2005-328458        Patent Reference 2: Japanese Unexamined Patent Application Publication No. 2006-74720        Patent Reference 3: Japanese Unexamined Patent Application Publication No. 2004-172719        Patent Reference 4: Japanese Unexamined Patent Application Publication No. 2000-115245        Patent Reference 5: Japanese Unexamined Patent Application Publication No. 2004-336768        Patent Reference 6: Japanese Patent No. 3662907        